Green manure synergist for rice field carbon sequestration and emission reduction and application thereof

Abstract

The invention discloses a green manure synergist for rice field carbon sequestration and emission reduction and application thereof, and belongs to the technical field of rice field green manure, the green manure synergist for rice field carbon sequestration and emission reduction comprises the following raw materials by mass: 3-5 kg of composite sepiolite, 0.2-0.5 kg of sodium 2-chloroethane sulfonate, 0.5-1 kg of immobilized bacterium biochar and 0.3-0.5 kg of goethite; according to the green manure synergist disclosed by the invention, the composite sepiolite, the sodium 2-chloroethane sulfonate, the immobilized bacterium biochar and the goethite are mixed according to a certain proportion, and the mixture is sown in a rice field in the full-bloom stage of the astragalus smicus and turned and pressed into soil together with the astragalus smicus; through the combined action of the immobilized bacterium biochar, the sodium 2-chloroethane sulfonate, the composite sepiolite and the goethite, the emission of greenhouse gases such as methane and nitrous oxide in the decomposition process of the astragalus sinicus is reduced, the soil carbon sequestration efficiency of returning the astragalus sinicus to the field is improved, the capacity expansion of a carbon reservoir is promoted, and the carbon sequestration and emission reduction of the green manure rice field are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of paddy field green manure, and specifically relates to a green manure synergist for carbon sequestration and emission reduction in paddy fields and its application. Background Art

[0002] Utilize seasonally or spatially idle land to plant (or raise) nitrogen-fixing or specific soil-improving crops, and turn over and return the green plant bodies of these crops to the field or cover the ground surface, providing nutrients and organic matter for farmland. These green plant bodies and root stubbles are called green manure. Green manure is an integral part of China's traditional farming civilization and an important technical and material means for the sustainable utilization of cultivated land in China for thousands of years. As a biological fertilizer, green manure is mainly applied to the soil by turning it over to improve soil structure and provide nutrients. The role of green manure in saving fertilizers and increasing yields and improving soil fertility has attracted the attention of the majority of agricultural scientific researchers and production entities.

[0003] A method for reducing the amount of chemical fertilizers and increasing the efficiency of paddy fields based on green manure with the publication number of CN116267157A sows milk vetch seeds and ryegrass seeds in paddy fields, and mixes the seeds with calcium magnesium phosphate fertilizer before sowing; leave the rice stubble after the late rice harvest, and dig trenches around the paddy fields; in the following year, urea is topdressed to the milk vetch and ryegrass during the seedling stage, and they are jointly turned over and returned to the field with the rice stubble during their full bloom stage, and sesbania charcoal and sepiolite are applied. After puddling the field, conventional harrowing, fertilization and early rice transplanting are carried out, achieving the effect of reducing the input of chemical fertilizers in paddy fields and promoting the increase of rice yields.

[0004] As the most commonly used leguminous green manure crop in paddy fields, milk vetch is an efficient means of expanding the soil carbon pool after being turned over and returned to the field. The average annual carbon sequestration amount (calculated as C) in the soil of milk vetch fields is 60 kg / mu more than that of winter fallow fields. However, polysaccharide substances such as cellulose and hemicellulose in its organic residues are hydrolyzed by aerobic bacteria and fungi to generate monosaccharides such as glucose and xylose, which are further metabolized into pyruvate through the glycolysis pathway, and short-chain organic acids such as acetic acid and propionic acid are generated by shunting. In an anaerobic microenvironment, some anaerobic bacteria will use these organic acids to synthesize a large amount of methane gas through the acetyl-CoA pathway, and the emission into the air will cause the risk of warming and the burden of environmental protection.

[0005] How to reasonably control and reduce greenhouse gas emissions during the rice production process while improving the productivity and soil fertility of paddy fields in a coordinated manner when turning over and returning green manure as a clean organic material to the field, and further improve the soil carbon sequestration capacity of paddy fields and reduce greenhouse gas emissions, has great ecological and environmental as well as practical production significance. Summary of the Invention

[0006] The object of the present invention is to provide a green manure synergist for carbon sequestration and emission reduction in paddy fields and its application. By compounding iron tetroxide onto a degradable water-absorbing resin, then filling the degradable water-absorbing resin into the pores of modified biochar, and spraying DAMO archaeal bacterial solution to obtain solidified bacterial biochar, and then mixing it with composite sepiolite introduced with mercapto and amino groups, and mixing it with milk vetch together, while reducing greenhouse gas emissions, it also increases the organic matter content in the soil, achieving the beneficial effects of carbon sequestration, nitrogen increase and soil fertilization, and solving the problem of a large amount of greenhouse gases generated during the degradation of milk vetch.

[0007] The object of the present invention can be achieved by the following technical solutions: A green manure synergist for carbon sequestration and emission reduction in paddy fields, comprising the following raw materials by mass: 3 - 5 parts of composite sepiolite, 0.2 - 0.5 part of 2-chloroethanesulfonic acid sodium, 0.5 - 1 part of solidified bacterial biochar, and 0.3 - 0.5 part of goethite.

[0008] The solidified bacterial biochar is prepared by the following steps: Step 1: Add sorbitan monooleate, carboxymethyl cellulose, cyclohexane, and modified iron tetroxide into a reaction kettle, react for 30 - 40 min under nitrogen protection and at 40 - 50 °C, add 2 mol / L sodium hydroxide solution and acrylic acid into the reaction kettle, react for 20 - 30 min under the conditions of 0 - 5 °C and 200 - 300 r / min, then add acrylamide, potassium persulfate, and N,N'-methylenebisacrylamide, react for 1 - 2 h under the condition of 70 - 80 °C, filter, wash, and dry to constant weight to obtain a composite degradable water-absorbing resin.

[0009] Step 2: Add the composite degradable water-absorbing resin, modified biochar, benzoyl peroxide, and acetone into a reaction kettle, perform vacuum impregnation for 4 h, filter, wash, and dry to obtain composite biochar.

[0010] Step 3: Spray the DAMO archaeal bacterial suspension on 2 - 4 kg of composite biochar, and dry to obtain solidified bacterial biochar.

[0011] Furthermore, the dosage ratio of sorbitan monooleate, carboxymethyl cellulose, cyclohexane, modified iron tetroxide, sodium hydroxide solution, acrylic acid, acrylamide, potassium persulfate, and N,N'-methylenebisacrylamide in Step 1 is 6 - 8 kg: 15 - 20 kg: 1000 - 1200 L: 8 - 10 kg: 90 - 100 L: 40 - 50 L: 16 - 18 kg: 0.5 - 1 kg: 0.5 - 0.8 kg.

[0012] Further, the dosage ratio of the composite degradable water-absorbing resin, modified biochar, benzoyl peroxide and acetone in step two is 15 - 20 kg : 8 - 10 kg : 150 g : 800 - 1000 L.

[0013] Further, the preparation process of the modified biochar is as follows: Put biochar with a particle size of 0.5 - 1 mm and 2 mol / L nitric acid solution into a reaction kettle, react at 80 - 120 °C and 200 - 500 r / min for 22 - 25 h, centrifuge, filter, wash, and dry to obtain modified biochar.

[0014] Further, the preparation process of the composite sepiolite is as follows: Put acidified sepiolite powder and 3 - mercaptopropyltrimethoxysilane into a reaction kettle, react at 20 - 25 °C and 500 - 800 r / min for 11 - 14 h, then put tetraethylenepentamine, polyethyleneimine and methanol into the reaction kettle, stir at 20 - 25 °C and 300 - 500 r / min for 20 - 24 h, filter, wash, and dry to obtain composite sepiolite.

[0015] Further, the dosage ratio of the acidified sepiolite powder, 3 - mercaptopropyltrimethoxysilane, tetraethylenepentamine, polyethyleneimine and methanol is 10 - 20 kg : 20 - 22 L : 8 - 10 L : 9 - 11 L : 80 - 100 L.

[0016] Further, the preparation process of the acidified sepiolite powder is as follows: Put sepiolite with a particle size of 0.5 - 1 mm into a muffle furnace at 150 - 180 °C for 3 - 5 h, naturally cool to room temperature, transfer the sepiolite to a reaction kettle, add 2 mol / L sulfuric acid solution, react at 70 - 90 °C and 300 - 500 r / min for 4 - 5 h, filter, wash, dry, and grind to obtain acidified sepiolite powder.

[0017] Further, the dosage ratio of sepiolite and sulfuric acid solution is 10 - 20 kg : 100 - 200 L.

[0018] Further, the preparation process of the modified iron oxide is as follows: Put iron oxide powder with a particle size of 30 - 50 nm, absolute ethanol and KH570 into a reaction kettle, react at 70 - 90 °C and 300 - 500 r / min for 5 - 6 h, filter, wash, and dry to obtain modified iron oxide.

[0019] The present invention also provides an application of a green manure synergist for carbon sequestration and emission reduction in paddy fields in reducing greenhouse gas emissions of Chinese milk vetch green manure.

[0020] The beneficial effects of the present invention: 1. The green manure synergist in the present invention mixes composite sepiolite, sodium 2-chloroethanesulfonate, solidified bacteria biochar and goethite in a certain proportion, sows it in the paddy field during the full-bloom period of milk vetch, and turns it over into the soil together with milk vetch. The solidified bacteria biochar and the composite sepiolite jointly reduce the emissions of greenhouse gases such as methane and nitrous oxide during the decomposition of milk vetch, or fix, absorb and decompose the greenhouse gases such as methane and nitrous oxide generated during the decomposition of milk vetch, and convert them into ammonium salts and the like that are beneficial to the absorption of rice roots, reducing the emissions of greenhouse gases during the decomposition of milk vetch. At the same time, it increases the content of soil carbon and nitrogen nutrients, realizes carbon sequestration and capacity increase, improves soil fertility, and provides a material basis for increasing rice yield and efficiency.

[0021] 2. In the solidified bacteria biochar of the present invention, modified iron tetroxide containing hydroxyl groups is first grafted onto carboxymethyl cellulose through a silane coupling agent to obtain a composite degradable water-absorbing resin. Then, the composite degradable resin is filled into the modified biochar. Utilizing its good water absorption and water retention effects, it can play a supporting role during volume expansion, making the spatial structure of the biochar more stable, which helps to provide a good growth and reproduction space for DAMO archaea, helps to improve the fixation effect on greenhouse gases such as methane and nitrous oxide, and reduces the emissions of greenhouse gases; and this composite degradable water-absorbing resin is easy to degrade and is more environmentally friendly. Modified iron tetroxide has a large specific surface area and abundant adsorption sites. Through physical adsorption and electrostatic interaction, etc., it enhances the adsorption of particulate organic carbon in the soil by the composite biochar, achieving soil carbon sequestration and fertility improvement, and providing a material basis for increasing rice yield. Specific embodiments

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] Example 1: This example provides a green manure synergist for carbon sequestration and emission reduction in paddy fields, which is prepared through the following steps: S1: Add 15 kg of biochar with a particle size of 0.5 - 1 mm and 150 L of a nitric acid solution with a concentration of 2 mol / L to the reaction kettle, react at 100 °C and 350 r / min for 23.5 h, centrifuge and filter at 8000 r / min for 5 min, wash the precipitate with deionized water 6 times, and dry it to constant weight at 110 °C to obtain modified biochar.

[0024] S2: Add 9 kg of iron tetroxide powder with a particle size of 30 - 50 nm, 220 L of absolute ethanol, and 450 g of KH570 into a reaction kettle, react for 5.5 h under the conditions of 80 °C and 400 r / min. An O - Si - O bond is formed between the hydroxyl groups on the surface of iron tetroxide and the Si - O bond of KH570. Centrifuge and filter, wash 4 times with deionized water, and vacuum dry at 70 °C until constant weight to obtain modified iron tetroxide. Add 7 kg of sorbitan monooleate, 17.5 kg of carboxymethyl cellulose, 1100 L of cyclohexane, and 9 kg of modified iron tetroxide into the reaction kettle, react for 35 min under the conditions of nitrogen protection, 45 °C, and 400 r / min. Add 95 L of sodium hydroxide solution with a concentration of 2 mol / L and 45 L of acrylic acid into the reaction kettle, react for 25 min under the conditions of 2 °C and 250 r / min. Then add 17 kg of acrylamide, 0.75 kg of potassium persulfate, and 0.65 kg of N,N´ - methylenebisacrylamide into the reaction kettle to graft iron tetroxide onto carboxymethyl cellulose, react for 1.5 h under the conditions of 75 °C, centrifuge and filter, wash the filter cake 3 times with absolute ethanol, and vacuum dry at 75 °C until constant weight to obtain a composite degradable water - absorbing resin.

[0025] S3: Add 17.5 kg of composite degradable water - absorbing resin, 9 kg of modified biochar, 150 g of benzoyl peroxide, and 900 L of acetone solution into a reaction kettle, vacuum impregnate for 4.5 h under the conditions of 0.09 MPa and 50 °C, centrifuge and filter, wash 4 times with deionized water, and dry at 45 °C until constant weight to obtain composite biochar.

[0026] S4: There are two groups of hollow - fiber membrane modules in a sequencing batch membrane - biofilm reactor. The membrane module is composed of 80 integrated hollow fibers, each fiber is 20 m long, with an inner diameter of 180 μm and an outer diameter of 280 μm. Use a pneumatic pressure reducing valve to connect a high - pressure gas cylinder loaded with methane and carbon dioxide gases to one of the hollow - fiber membrane gas paths, and connect the other hollow - fiber membrane gas path to a high - pressure gas cylinder loaded with oxygen. Install the sequencing batch membrane - biofilm reactor in 700 L of inorganic salt medium, inoculate 120 L of sludge containing DAMO archaea in the inorganic salt medium at 30 °C, add a concentrated medium containing ammonia nitrogen and nitrite nitrogen, and pass oxygen into the inorganic salt medium through the hollow fibers at 13 - 28 d, with a dissolved oxygen content of 0.2 mg / L. Add a deoxidizer at a concentration of 0.5 g / L at 80 - 120 d to obtain an enriched DAMO archaea bacterial solution.

[0027] S5: Spray 500 mL of DAMO archaea bacterial suspension with a concentration of 4×10 8 cfu / mL on 3 kg of composite biochar, and dry until the water content is 45% to obtain solidified bacteria biochar.

[0028] S6: Place 15 kg of sepiolite with a particle size of 0.5 - 1 mm in a muffle furnace at 165 °C for 4 h, and let it cool naturally to room temperature. Transfer 15 kg of sepiolite to a reaction kettle, add 150 L of sulfuric acid solution with a concentration of 2 mol / L, react at 80 °C and 400 r / min for 4.5 h, centrifuge and filter, wash the filter cake 4 times with deionized water, dry it to constant weight at 105 °C, grind it and pass it through a 100-mesh sieve to obtain acidified sepiolite powder; add 15 kg of acidified sepiolite powder and 21 L of 3-mercaptopropyltrimethoxysilane to the reaction kettle, react at 20 - 25 °C and 650 r / min for 12.5 h to graft the mercapto group onto the sepiolite, add 9 L of tetraethylenepentamine, 10 L of polyethyleneimine and 90 L of methanol to the reaction kettle, stir at 20 - 25 °C and 400 r / min for 22 h to insert tetraethylenepentamine and polyethyleneimine into the layer-chain structure of the sepiolite, centrifuge and filter, wash it 3 times with methanol, dry it to constant weight at 80 °C to obtain composite sepiolite.

[0029] S7: Mix 4 kg of composite sepiolite, 0.35 kg of 2-chloroethanesulfonate, 0.75 kg of solidified bacteria biochar and 0.4 kg of goethite evenly to obtain a green manure synergist for carbon sequestration and emission reduction in paddy fields.

[0030] Example 2: This example provides a green manure synergist for carbon sequestration and emission reduction in paddy fields, which is prepared by the following steps: S1: Add 10 kg of biochar with a particle size of 0.5 - 1 mm and 100 L of nitric acid solution with a concentration of 2 mol / L to a reaction kettle, react at 80 °C and 200 r / min for 22 h, centrifuge and filter at 8000 r / min for 5 min, wash the precipitate 5 times with deionized water, dry it to constant weight at 100 °C to obtain modified biochar.

[0031] S2: Add 8 kg of iron oxide (Fe₃O₄) powder with a particle size of 30 - 50 nm, 200 L of absolute ethanol, and 400 g of KH570 into a reaction kettle, and react for 5 h under the conditions of 70 °C and 300 r / min. An O - Si - O bond is formed between the hydroxyl groups on the surface of iron oxide and the Si - O bonds of KH570. Then, centrifuge and filter, wash 3 times with deionized water, and vacuum dry at 60 °C until constant weight to obtain modified iron oxide. Add 6 kg of sorbitan monooleate, 15 kg of carboxymethyl cellulose, 1000 L of cyclohexane, and 8 kg of modified iron oxide into the reaction kettle, and react for 30 min under the conditions of nitrogen protection, 40 °C, and 300 r / min. Add 90 L of sodium hydroxide solution with a concentration of 2 mol / L and 40 L of acrylic acid into the reaction kettle, and react for 20 min under the conditions of 0 °C and 200 r / min. Then, add 16 kg of acrylamide, 0.5 kg of potassium persulfate, and 0.5 kg of N,N´ - methylenebisacrylamide into the reaction kettle to graft the iron oxide onto the carboxymethyl cellulose, and react for 1 h under the conditions of 70 °C. Centrifuge and filter, wash the filter cake 2 times with absolute ethanol, and vacuum dry at 70 °C until constant weight to obtain the composite degradable water - absorbent resin.

[0032] S3: Add 15 kg of composite degradable water - absorbent resin, 8 kg of modified biochar, 150 g of benzoyl peroxide, and 800 L of acetone solution into a reaction kettle, and vacuum impregnate for 4 h under the conditions of 0.08 MPa and 40 °C. Centrifuge and filter, wash 3 times with deionized water, and dry at 40 °C until constant weight to obtain the composite biochar.

[0033] S4: There are two groups of hollow - fiber membrane modules in the sequencing - batch membrane biofilm reactor. The membrane module is integrated by 80 hollow fibers, each fiber is 20 m long, with an inner diameter of 180 μm and an outer diameter of 280 μm. Use a pneumatic pressure reducing valve to connect a high - pressure gas cylinder loaded with methane and carbon dioxide gases to one of the hollow - fiber membrane gas paths, and connect the other hollow - fiber membrane gas path to a high - pressure gas cylinder loaded with oxygen. Install the sequencing - batch membrane biofilm reactor in 700 L of inorganic salt medium, inoculate 120 L of sludge containing DAMO archaea in the inorganic salt medium at 29 °C, add a concentrated medium containing ammonia nitrogen and nitrite nitrogen, and introduce oxygen into the inorganic salt medium through the hollow fiber at 13 - 28 d, with a dissolved oxygen content of 0.2 mg / L. Add 0.5 g / L of deoxidizer at 80 - 120 d to obtain an enriched DAMO archaea bacterial liquid.

[0034] S5: Spray 500 mL of DAMO archaea bacterial suspension with a concentration of 4×10 8 cfu / mL on 2 kg of composite biochar, and dry until the water content is 40% to obtain the immobilized bacteria biochar.

[0035] S6: Place 10 kg of sepiolite with a particle size of 0.5 - 1 mm in a muffle furnace at 150 °C for 3 h, and let it cool naturally to room temperature. Transfer 10 kg of sepiolite to a reaction kettle, add 100 L of sulfuric acid solution with a concentration of 2 mol / L, react at 70 °C and 300 r / min for 4 h, carry out centrifugal filtration, wash the filter cake 3 times with deionized water, dry it to constant weight at 100 °C, grind it and then pass it through a 100-mesh sieve to obtain acidified sepiolite powder; add 10 kg of acidified sepiolite powder and 20 L of 3-mercaptopropyltrimethoxysilane to the reaction kettle, react at 20 - 25 °C and 500 r / min for 11 h to graft the mercapto group onto the sepiolite. Add 8 L of tetraethylenepentamine, 9 L of polyethyleneimine and 80 L of methanol to the reaction kettle, stir at 20 - 25 °C and 300 r / min for 20 h to insert tetraethylenepentamine and polyethyleneimine into the layer-chain structure of the sepiolite, carry out centrifugal filtration, wash it 2 times with methanol, dry it to constant weight at 80 °C to obtain composite sepiolite.

[0036] S7: Mix 3 kg of composite sepiolite, 0.2 kg of 2-chloroethanesulfonate, 0.5 kg of solidified bacteria biochar and 0.3 kg of goethite evenly to obtain a green manure synergist for carbon sequestration and emission reduction in paddy fields.

[0037] Example 3: This example provides a green manure synergist for carbon sequestration and emission reduction in paddy fields, which is prepared through the following steps: S1: Add 20 kg of biochar with a particle size of 0.5 - 1 mm and 200 L of nitric acid solution with a concentration of 2 mol / L to a reaction kettle, react at 120 °C and 500 r / min for 25 h, carry out centrifugal filtration at 8000 r / min for 5 min, wash the precipitate 8 times with deionized water, and dry it to constant weight at 120 °C to obtain modified biochar.

[0038] S2: Add 10 kg of iron tetroxide powder with a particle size of 30 - 50 nm, 250 L of absolute ethanol, and 500 g of KH570 into a reaction kettle, react for 6 h under the conditions of 90 °C and 500 r / min. An O - Si - O bond is formed between the hydroxyl groups on the surface of iron tetroxide and the Si - O bonds of KH570. Centrifuge and filter, wash 5 times with deionized water, and vacuum dry to constant weight at 80 °C to obtain modified iron tetroxide. Add 8 kg of sorbitan monooleate, 20 kg of carboxymethyl cellulose, 1200 L of cyclohexane, and 10 kg of modified iron tetroxide into the reaction kettle, react for 40 min under the protection of nitrogen, at 50 °C and 500 r / min. Add 100 L of sodium hydroxide solution with a concentration of 2 mol / L and 50 L of acrylic acid into the reaction kettle, react for 30 min at 5 °C and 300 r / min. Then add 18 kg of acrylamide, 1 kg of potassium persulfate, and 0.8 kg of N,N´ - methylenebisacrylamide into the reaction kettle, graft the iron tetroxide onto the carboxymethyl cellulose, react for 2 h at 80 °C, centrifuge and filter, wash the filter cake 3 times with absolute ethanol, and vacuum dry to constant weight at 80 °C to obtain a composite degradable water - absorbing resin.

[0039] S3: Add 20 kg of composite degradable water - absorbing resin, 10 kg of modified biochar, 150 g of benzoyl peroxide, and 1000 L of acetone solution into a reaction kettle, vacuum impregnate for 5 h under the conditions of 0.1 MPa and 60 °C, centrifuge and filter, wash 5 times with deionized water, and dry to constant weight at 50 °C to obtain composite biochar.

[0040] S4: There are two groups of hollow - fiber membrane modules in the sequencing batch membrane biofilm reactor. The membrane module is integrated by 80 hollow fibers, each fiber is 20 m long, with an inner diameter of 180 μm and an outer diameter of 280 μm. Use a pneumatic pressure reducing valve to connect a high - pressure gas cylinder loaded with methane and carbon dioxide gases to one of the hollow - fiber membrane gas paths, and connect the other hollow - fiber membrane gas path to a high - pressure gas cylinder loaded with oxygen. Install the sequencing batch membrane biofilm reactor in 700 L of inorganic salt medium, inoculate 120 L of sludge containing DAMO archaea in the inorganic salt medium at 31 °C, add a concentrated medium containing ammonia nitrogen and nitrite nitrogen, and introduce oxygen into the inorganic salt medium through the hollow fibers at 13 - 28 d, with a dissolved oxygen content of 0.2 mg / L. Add a deoxidizer at 0.5 g / L at 80 - 120 d to obtain an enriched DAMO archaea bacterial liquid.

[0041] S5: Spray 500 mL of DAMO archaea bacterial suspension with a concentration of 4×10 8 cfu / mL on 4 kg of composite biochar, and dry to a water content of 50% to obtain solidified bacteria biochar.

[0042] S6: Place 20 kg of sepiolite with a particle size of 0.5 - 1 mm in a muffle furnace at 180 °C for 5 h, and let it cool naturally to room temperature. Transfer 20 kg of sepiolite to a reaction kettle, add 200 L of sulfuric acid solution with a concentration of 2 mol / L, react at 90 °C and 500 r / min for 5 h, centrifuge and filter. Wash the filter cake 5 times with deionized water, dry it to constant weight at 110 °C, grind it and pass it through a 100 - mesh sieve to obtain acidified sepiolite powder. Add 20 kg of acidified sepiolite powder and 22 L of 3 - mercaptopropyltrimethoxysilane to the reaction kettle, react at 20 - 25 °C and 800 r / min for 14 h to graft the mercapto group onto the sepiolite. Add 11 L of tetraethylenepentamine, 11 L of polyethyleneimine and 100 L of methanol to the reaction kettle, stir at 20 - 25 °C and 500 r / min for 24 h to insert tetraethylenepentamine and polyethyleneimine into the layer - chain structure of sepiolite. Centrifuge and filter, wash it 5 times with methanol, dry it to constant weight at 80 °C to obtain composite sepiolite.

[0043] S7: Mix 5 kg of composite sepiolite, 0.5 kg of 2 - chloroethanesulfonate, 1 kg of solidified bacteria biochar and 0.5 kg of goethite evenly to obtain a green manure synergist for paddy field carbon sequestration and emission reduction.

[0044] Comparative Example 1: The difference from Example 1 is that in S7, ordinary biochar is used instead of solidified bacteria biochar, and the rest of the steps remain unchanged, to prepare a green manure synergist for paddy field carbon sequestration and emission reduction.

[0045] Comparative Example 2: The difference from Example 1 is that in S7, ordinary sepiolite is used instead of composite sepiolite, and the rest of the steps remain unchanged, to prepare a green manure synergist for paddy field carbon sequestration and emission reduction.

[0046] Comparative Example 3: The difference from Example 1 is that in S7, composite biochar is used instead of solidified bacteria biochar, and the rest of the steps remain unchanged, to prepare a green manure synergist for paddy field carbon sequestration and emission reduction.

[0047] Fertilizer efficiency tests were conducted on the green manure synergists prepared in Examples 1 - 3 and Comparative Examples 1 - 3. Test site: Experimental demonstration base in Luoshan County, Xinyang City, Henan Province. Fields with medium or above soil fertility levels were selected. The green manure demonstration test fields were divided into 7 plots, each plot with an area of 667 square meters. The green manure Chinese milk vetch variety planted was "Xinzi No. 1", and the rice varieties were all the local popular varieties. Machine transplanting was used for planting, and field management was carried out according to the requirements of conventional cultivation techniques. The prevention and control of pests, diseases and weeds were the same as the local farmland management measures. Before turning under the green manure, it was necessary to measure the yield of the Chinese milk vetch. The green manure yield should reach 1500 kg / mu or more. One day before turning under the green manure, the green manure synergists prepared in Examples 1 - 3 and Comparative Examples 1 - 3 were scattered by drone, with an application rate of 20 kg / mu. A blank control group ck was set up without applying the green manure synergist. During the full bloom period of Chinese milk vetch, the Chinese milk vetch and the rice straw of the previous season were turned under the field together, with a turning depth of 15 - 20 cm, to make it fully mixed with the soil. 5 - 8 cm of water was irrigated for retting the field 7 - 10 days after turning under, and the field was harrowed and leveled and rice was planted 10 - 15 days after retting. The initial soil data were: pH value: 5.67, total nitrogen: 0.93 g / kg, organic matter: 14.52 g / kg, available phosphorus: 10.55 mg / kg, available potassium: 65.05 mg / kg. The experimental data were averaged, and the implementation period was from 2021 to 2024. The cumulative emissions of methane and nitrous oxide gases were measured. GWP represents the global warming potential, and GHGI represents the greenhouse gas emission intensity.

[0048] The data of the rice yield per mu are shown in Table 1: Table 1 Data table of rice yield per mu Project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 ck Yield per mu (kg / mu) 651.3 672.2 665.5 604.2 610.2 620.5 585.2 Effective panicle number (10,000 / mu) 18.08 18.12 18.05 17.64 17.72 17.83 17.45 Total grains per panicle (grains) 176.9 179.8 177.5 171.2 171.6 172.3 168.2 Seed setting rate (%) 90.9 90.8 90.7 89.5 89.7 89.6 88.1 1000-grain weight (g) 26.8 26.9 26.9 26.2 26.5 26.3 26.2 As can be seen from Table 1, the rice yield per mu in Examples 1 - 3 was higher than that of ck, and the rice yield per mu in Comparative Examples 1 - 3 was lower than that in Examples 1 - 3. This shows that after mixing solidified bacteria biochar, composite sepiolite, etc. and turning them under the soil together with Chinese milk vetch, by increasing the effective panicles and total grains per panicle in the rice yield components, it can play a synergistic effect in increasing the rice yield per mu and improve the rice yield per mu to a certain extent.

[0049] Table 2 Influence of green manure synergist on greenhouse gas emission effect As can be seen from Table 2, the cumulative emissions of methane and nitrous oxide during the rice growth process in Examples 1 - 3 are all less than those in the ck group. In Comparative Example 1, ordinary biochar is used instead of the immobilized bacteria biochar, and the cumulative emissions of methane and nitrous oxide are decreased compared with those in the ck group. In Comparative Example 2, ordinary sepiolite is used instead of the composite sepiolite, and the cumulative emissions of methane and nitrous oxide are decreased compared with those in the ck group. In Comparative Example 3, composite biochar is used instead of the immobilized bacteria biochar, and the cumulative emissions of methane and nitrous oxide are decreased compared with those in the ck group, but are higher than those in Examples 1 - 3. This shows that when the green manure synergist containing immobilized bacteria biochar and composite sepiolite is incorporated into the soil by turning over and mixing with Chinese milk vetch, it can effectively reduce the emissions of methane, nitrous oxide and nitrogen oxides during the whole process from turning over Chinese milk vetch to rice harvest.

[0050] Table 3 Effects of Green Manure Synergist on Soil Nutrients Project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 ck Organic matter (g / kg) 16.79 17.14 16.88 14.21 13.25 13.45 14.21 Total nitrogen (g / kg) 1.05 1.11 1.08 0.95 1.03 0.91 0.95 Available phosphorus (mg / kg) 13.96 13.01 14.21 12.55 11.01 12.85 10.44 Available potassium (mg / kg) 81.11 79.25 80.15 75.04 78.14 80.04 65.21 pH value 6.01 6.04 5.96 5.84 5.69 5.71 5.68 As can be seen from Table 3, the contents of organic matter, total nitrogen, available phosphorus and available potassium in the soil in Examples 1 - 3 are all higher than those in the ck group, indicating that the green manure synergist for carbon sequestration and emission reduction in paddy fields in the present invention can effectively improve soil nutrients after being intercropped with Chinese milk vetch.

[0051] It should be noted that in this text, terms such as "including", "comprising" or any other variants thereof are intended to cover non - exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements but also includes other elements not explicitly listed, or further includes elements inherent to such a process, method, article or device.

[0052] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. A green manure synergist for carbon sequestration and emission reduction in paddy fields, characterized in that, It includes the following raw materials by mass parts: 3 - 5 parts of composite sepiolite, 0.2 - 0.5 part of 2 - chloroethanesulfonic acid sodium, 0.5 - 1 part of solidified bacteria biochar, and 0.3 - 0.5 part of goethite; The solidified bacteria biochar is prepared through the following steps: Step 1: Add sorbitan monooleate, carboxymethyl cellulose, cyclohexane, and modified magnetite into a reaction kettle, react for 30 - 40 min under nitrogen protection and at 40 - 50 °C, add a sodium hydroxide solution with a concentration of 2 mol / L and acrylic acid into the reaction kettle, react for 20 - 30 min at 0 - 5 °C and 200 - 300 r / min, then add acrylamide, potassium persulfate, and N,N´-methylenebisacrylamide, react for 1 - 2 h at 70 - 80 °C, filter, wash, and dry to obtain a composite degradable water-absorbing resin; Step 2: Add the composite degradable water-absorbing resin, modified biochar, benzoyl peroxide, and acetone into a reaction kettle, carry out vacuum impregnation for 4 h, filter, wash, and dry to obtain a composite biochar; Step 3: Spray the DAMO archaeal suspension on 2 - 4 kg of the composite biochar, and dry to obtain the solidified bacteria biochar.

2. The green manure synergist for carbon sequestration and emission reduction in paddy fields according to claim 1, wherein In Step 1, the dosage ratio of sorbitan monooleate, carboxymethyl cellulose, cyclohexane, modified magnetite, sodium hydroxide solution, acrylic acid, acrylamide, potassium persulfate, and N,N´-methylenebisacrylamide is 6 - 8 kg: 15 - 20 kg: 1000 - 1200 L: 8 - 10 kg: 90 - 100 L: 40 - 50 L: 16 - 18 kg: 0.5 - 1 kg: 0.5 - 0.8 kg.

3. The green manure synergist for carbon sequestration and emission reduction in paddy fields according to claim 1, characterized in that, In Step 2, the dosage ratio of the composite degradable water-absorbing resin, modified biochar, benzoyl peroxide, and acetone is 15 - 20 kg: 8 - 10 kg: 150 g: 800 - 1000 L.

4. The green manure synergist for carbon sequestration and emission reduction in paddy fields according to claim 3, wherein The preparation process of the modified biochar is as follows: Add biochar with a particle size of 0.5 - 1 mm and a 2 mol / L nitric acid solution into a reaction kettle, react for 22 - 25 h at 80 - 120 °C and 200 - 500 r / min, centrifuge and filter, wash, and dry to obtain the modified biochar.

5. A green manure synergist for carbon sequestration and emission reduction in paddy fields according to claim 1, characterized in that, The preparation process of the composite sepiolite is as follows: Add acidified sepiolite powder and 3 - mercaptopropyltrimethoxysilane into a reaction kettle, react for 11 - 14 h at 20 - 25 °C and 500 - 800 r / min, add tetraethylenepentamine, polyethyleneimine, and methanol into the reaction kettle, stir for 20 - 24 h at 20 - 25 °C and 300 - 500 r / min, filter, wash, and dry to obtain the composite sepiolite.

6. The green manure synergist for carbon sequestration and emission reduction in paddy fields according to claim 5, wherein The dosage ratio of the acidified sepiolite powder, 3 - mercaptopropyltrimethoxysilane, tetraethylenepentamine, polyethyleneimine, and methanol is 10 - 20 kg: 20 - 22 L: 8 - 10 L: 9 - 11 L: 80 - 100 L.

7. The green manure synergist for carbon sequestration and emission reduction in paddy fields according to claim 5, characterized in that, The preparation process of the acidified sepiolite powder is as follows: The sepiolite with a particle size of 0.5 - 1 mm is placed in a muffle furnace at 150 - 180 °C for 3 - 5 h, and then naturally cooled to room temperature. The sepiolite is transferred to a reaction kettle, and a 2 mol / L sulfuric acid solution is added. The reaction is carried out at 70 - 90 °C and 300 - 500 r / min for 4 - 5 h, followed by filtration, washing, drying, and grinding to obtain acidified sepiolite powder.

8. The green manure synergist for carbon sequestration and emission reduction in paddy fields according to claim 7, characterized in that, The dosage ratio of the sepiolite to the sulfuric acid solution is 10 - 20 kg: 100 - 200 L.

9. A green manure synergist for carbon sequestration and emission reduction in paddy fields according to claim 2, characterized in that, The preparation process of the modified iron tetroxide is as follows: The iron tetroxide powder with a particle size of 30 - 50 nm, anhydrous ethanol, and KH570 are added to a reaction kettle, and the reaction is carried out at 70 - 90 °C and 300 - 500 r / min for 5 - 6 h. After filtration, washing, and drying, the modified iron tetroxide is obtained.

10. Application of a green manure synergist for carbon sequestration and emission reduction in paddy fields in reducing greenhouse gas emissions during the decomposition of milk vetch and the growth of rice according to claim 1.

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